The advent of digital lighting technologies, i.e. illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offers a viable alternative to traditional fluorescent, HID, and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, robustness, lower operating costs, and many others. The LEDs' smaller size, long operating life, low energy consumption, and durability make them a great choice in a variety of lighting applications. For example, it is becoming increasingly popular to create lighting networks of LED-based devices, as described in U.S. Pat. Nos. 6,016,038, 6,150,774 and 6,166,496, all incorporated herein by reference. These lighting devices have integral microprocessors for controlling LED light sources therein and can produce any color and any sequence of colors at varying intensities and saturations, enabling a wide range of eye-catching lighting effects, in both illumination and direct-view applications.
These lighting systems and the effects they produce are generally controlled and coordinated through a network (although there are many non-networked applications), wherein a data stream containing packets of information is communicated to the lighting devices. Each of the lighting devices may register all of the packets of information passed through the system, but only respond to packets that are addressed to the particular device. Once a properly addressed packet of information arrives, the lighting device may read the packet and execute commands based on information contained in the packet. This arrangement demands that each of the lighting devices has an address and these addresses need to be unique with respect to the other lighting devices on the network. The addresses are normally set by setting switches on each of the lighting devices during installation. Settings switches tends to be time consuming and error prone.
Lighting systems for entertainment, retail, and architectural venues, such as theaters, casinos, theme parks, stores, and shopping malls, require an assortment of elaborate lighting fixtures and control systems to operate the lights. Conventional networked lighting devices have their addresses set through a series of physical switches such as dials, dipswitches or buttons. These devices have to be individually set to particular addresses and this process can be cumbersome. In fact, one of the lighting designers' most onerous tasks—system configuration—comes after all the lights are installed. This task typically requires at least two people and involves going to each lighting instrument or fixture and determining and setting the network address for it through the use of switches or dials and then determining the setup and corresponding element on a lighting board or computer. Not surprisingly, the configuration of a lighting network can take many hours, depending on the location and complexity. For example, a new amusement park ride may use hundreds of network-controlled lighting fixtures, which are neither line-of-sight to each other or to any single point. Each one must be identified and linked to its setting on the lighting control board. Mix-ups and confusion are common during this process. With sufficient planning and coordination this address selection and setting can be done a priori but still requires substantial time and effort.
There are several other disadvantages associated with these lighting systems, particularly with those designed for direct view applications. Specifically, there are many installations that require long lines of component fixtures placed in a row or other pattern in an attempt to produce a continuous light line to display a visually-pleasing effect for the viewer, for example, to outline the perimeter of a building with accent lighting. Conventional lighting networks, however, often produce little or no light in the gaps between adjoining fixtures, which tend to detract from the intended appearance of these installations. In addition, because each of the components is addressed individually, the degree of coordination of the lighting effects, i.e. “resolution” of the application, is limited to the size of the components. For example, in a linear installation having a number of 1-foot long components, the components cannot be addressed any finer than in 1-foot increments. Also, another disadvantage of these systems is that when the LEDs are directly viewed they appear to be discrete light emitters until there is sufficient distance between the light and the viewer. Even when the viewer is relatively far away from the lighting system, the lighting system does not tend to produce very bright or clearly perceivable lighting effects.
Another shortcoming associated with many conventional lighting systems is that their components are externally powered, such that both communication and power lines are fed through the ends of the housing and into junction boxes at the beginning and end of every component fixture. The three lines, power, ground, and data, are run through each end and then passed through the length of the fixture. Each lighting element in the housing would tap into the three lines for power and data. Mounting of the fixtures is very expensive and cumbersome because it is implemented through junction boxes. Every light requires two junction boxes to be mounted on the wall or other mounting surface, and wires and conduit need to be run between boxes to allow two lighting units to be connected together.
Accordingly, there is a need in the art for versatile LED-based lighting fixtures capable of creating visually-pleasing color and color-changing lighting effects with enhanced control resolution and efficient power management, which are easy to install in a network.